DOPPLER-FREE 2-PHOTON SPECTROSCOPY OF NEON .3. ISOTOPIC SHIFT AND FINE-STRUCTURE FOR THE 2P5 4D AND 2P5 5S CONFIGURATIONS

The isotopic shift **2**0Ne-**2**2Ne for two-photon transitions between the 3s left bracket 3/2 right bracket 2 metastable state and the excited states of the 2p**5 4d and 2p**5 5s configurations was measured using Doppler-free two-photon spectroscopy. The results are analyzed using the specific mass shift theory. It is shown that the expansion of the **1P Russel-Saunders term over the true eigenstates of the atom can be deduced from the experimental data. Experimental determinations of the radial integrals J(4d, 2p) and J(5s, 2p) are also obtained. All the experimental results are in good agreement with theoretical predictions of Bauche and Liberman.